Analyses of liquid and vapor flow in a miniature radially rotating heat pipe for turbine blade cooling applications

Liquid film distributions and vapor flow in a radially rotating heat pipe are analyzed for potential heat transfer limitations under turbine blade cooling conditions. Closed-form analytical solutions for the liquid film in the condenser section and the vapor temperature drop along the heat pipe length are derived. The emphases in the present study are placed on the miniature size of the radially rotating heat pipe with a high rotating speed and high temperature. The ranges of heat inputs, geometric dimensions, and the rotating speeds are as follows: 40 less than or equal to Q less than or equal to 200 w, 1.0 less than or equal to D-h less than or equal to 8.0 mm, L = 80 mm, and 6.26 less than or equal to omega(2) (Z) over bar/g less than or equal to 6.26 x 10(4). It is found that the hear pipe diameter, radially rotating speed, and operating temperature play an important role on the performance of the heal pipe. Heat transfer limitations may be encountered for an increased heat input and rotating speed, or a decreased hydraulic diameter. Based on the extensive analytical evaluations, it is concluded that the miniature radially rotating heat pipe studied in this paper is feasible for turbomachinery applications.